Nowadays, since the cost of materials such as wood, metal, iron, gypsum etc. is high, composite materials that can be substituted for the above mentioned materials are produced.
Thermoplastic composite materials are mainly produced by processing plastic materials and adding various chemical and other additives into the plastics. The aim of these additions is to improve the mechanical and chemical properties of the thermoplastic materials without increasing costs. Nevertheless, the manufactured thermoplastics do not have the desired cost. This situation also makes it harder to use these materials in construction and building industries.
Now recycling methods are also used in obtaining thermoplastic composite materials. It is more preferable to obtain plastic materials that will be used in the thermoplastic composite materials from the waste plastics collected from the garbage, both from an economical and an environmental point of view. However, when materials on the waste plastics such as dirt, oil, chemicals etc. can not be removed completely, the quality of the obtained thermoplastic composite material gets lower.
The recycling methods of the waste plastic materials mainly consist of the following steps; separation of the waste plastics from the foreign materials, cutting the plastic materials into small pieces, melting and casting into desired molds, cooling and obtaining the desired product. Besides, various thermoplastic composite materials are produced by adding additives to plastic materials during this above mentioned melting process.
In the Japanese patent document No. JP 2007130885 of the known state of the art, a high strength, good endurance and long life composite material production system is disclosed. In this method, the emphasized process is primarily to determine the amount and size of the additive that will be given to the plastic. Secondly, the amount and type of the additive is determined. The 3rd step is about melting the mixture and controlling the pre-determined amount and type of the additive of the mixture formed in the mold.
In the Japanese patent document No. JP 2009132939 of the known state of the art, a durable composite material production technique is disclosed wherein waste plastic materials are used as raw material and additives are mixed in. The recyclable plastic first contains polymer and secondly polymer and residual additives.
In the Japanese patent document No. JP 2010234812 of the known state of the art, a high strength, good endurance and long life plastic mold production method is disclosed by employing various techniques and methods. For recycling waste plastic materials that contains 2 or more additives, the waste material is separated from the foreign materials, then melted and molded, respectively. The metal is separated from the plastic by mixture filtration method and after determination of the type and amount of additive, the separated metal and the additives are added to the recyclable plastic.
In the Japanese patent document No. JP 2004042461 of the known state of the art, the management of the processes such as washing off the dirt, oil, earth, undesired chemicals and food wastes on the waste plastics that contain foreign materials, separation and drying is disclosed. The recyclable plastic material is powdered in a liquid by cutting into small pieces. Then the plastic material is adhered or the materials contained within are separated from the plastic. The materials that indicate their positions are separated by liquid separation, plastic or plastic melting.
However, the amount of additives that will be mixed into the plastic materials is very important for the strength of the products to be obtained. When more additives (chemicals or minerals) can be added, the strength of the obtained material becomes proportionally higher. But, as high amounts of additives are mixed into the waste plastics, the melting of this mixture becomes more problematic. Usually these procedures are performed in extruder machines. In extruders, plastic waste materials and additives are fed in and composite material in dough form is obtained. In this situation, when a high amount of additive is mixed into the mixture, wearing and break downs occur in the machines, when the additives are used in low amounts the materials can not achieve the desired strength properties.
In the plastic processing machines that are used in the known state of the art that run by systems such as injection and extrusion, the working principle is forcing the melted material under pressure to exit through a hole. In the system, there is a feeding zone (a cone or a side feeding screw), a worm gear (also called as an Archimedes screw, it has compression and pushing tasks) and a cylindrical body (shell) where the gear moves inside and that can resist high pressures and temperatures up to 500° C. This situation increases the production and operation costs of the machine.
Moreover, in the plastic processing machines that are used in the known state of the art that run by systems such as injection and extrusion, more wearing occurs on the machines since the filler materials that have hard and abrasive properties are fed starting from the thermoplastic feeding zone. This situation increases the maintenance and repairment costs of the machine.
Furthermore, in the plastic processing machines that are used in the known state of the art that run by systems such as injection and extrusion, when the melted mixture reaches the compression zone, it can not be compressed since the minerals are not compressible and it causes the gear to be jammed or broken by generating very high counter torque forces. Therefore, high amounts of minerals are not used in melted thermoplastic mixtures and the mixture can not reach the desired strength value.
Moreover, in the plastic processing machines that are used in the known state of the art that run by systems such as injection and extrusion, very special molds need to be used. The price of these molds is very high.
Furthermore, in the plastic processing machines that are used in the known state of the art that run by systems such as injection and extrusion, the material is injected into the mold by the machine itself and also the required pressure is generated by the machine itself. Therefore, these machines are very complicated and expensive.
Moreover, in the plastic processing machines that are used in the known state of the art that run by systems such as injection and extrusion, since the molds are attached to the machine, the machines should not work while the material is cooling in the mold. As a result, these system runs by a start and stop principle and their production capacity is low.
Another problem is waiting the cool-down period after pressing the plastic material in dough form into a mold. In this situation, the machines can not run until the composite material in the mold cools.